As the responsibility of R&D spending in the oil field shifts to service companies, many new technologies are introduced as tools. Combining multiple tools or processes can present new and exciting answers to old intervention challenges.

This paper describes coiled tubing operations using a newly developed straddling system on two particular wells that were producing from several perforated intervals. The key to both operations was to first isolate each zone, perform injectivity testing at varying flow rates, and then to stimulate each zone at a rate below fracture pressure. The initial challenge was the large number of zones—16 zones in the first well and 14 zones in the second well—leading to the requirement to have multisettable technology in order to complete the individual zonal treatments in as few runs into the well as possible. The second challenge entailed the need for accurate depth control to ensure the zones were correctly straddled to allow for optimum treatment. If the packer elements were not set in the exact place, the treatment could be misplaced. A wireless casing collar locator (CCL) with pump-through capability, contained as standard within the tool, was used, delivering accurate, real-time depth readings without any added limitations or further runs in the well.

Inflatable technology was preferred over the conventional mechanical-cup isolation because of subsidence in the area and casing integrity concerns. Based on laboratory testing of the two reservoir types, two chemical systems were selected for the stimulation treatment; one was hydrofluoric clay acid-based and another xylene-based. Both chemicals are known to be chemically aggressive to the conventional rubber seals and elastomers found in inflatable technology. It was imperative that the inflatable could withstand these chemicals for the treatment to succeed. Multiple setting of the tool was completed by using flow pattern recognition devices in the tool. Sending individual pumping sequences from the surface through the coiled tubing to the tool accessed the different modes alternating between inflation, injection, circulation, and deflation mode. A feedback signal from the tool was received at the surface as a confirmation that the tool had correctly actuated to the desired mode.

A real-time correlation log was created; the inflatable packer was multiset on depth, injectivity testing took place and the clay acid- and xylene-based stimulations were pumped into all zones. The multiple technologies were combined in an innovative application that met all objectives of the operation.

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